Aim: This study aimed to investigate reasons for ceasing participation in aqua-based exercise among older adults with osteoarthritis (OA). Methods: Eleven adults over 60 years of age with OA participated in one of two focus groups, during which they discussed barriers to aqua-based exercise and the potential benefits of this exercise mode. Each focus group was audiotaped, transcribed and then analysed using the general inductive thematic approach. The investigators reached a consensus on all coding categories and then identified themes. Results: Key barriers identified were: a lack of suitable classes; insufficient instructor knowledge, which often led to increased pain; cold water and the changing facilities. Key perceived benefits included increased physical ability in water and social interaction. Conclusions: A greater understanding of reasons for ceasing participation in aqua-based exercise among older adults with OA may help facilitate development of suitable exercise programs that minimise barriers for this group.